Construction of a molecularly imprinted fluorescent sensor based on an amphiphilic block copolymer-metal–organic framework for the detection of oxytetracycline in milk

Abstract

A metal–organic framework (MOF) is a good carrier for molecular imprinting due to its high surface area and strong adsorption capacity, but its poor dispersibility in aqueous solution is one of the significant drawbacks, which can severely impede its effectiveness. Amphiphilic block copolymers are good hydrophilic materials and have the potential to overcome the shortcomings of MOFs. In order to improve the hydrophilicity of molecularly imprinted fluorescent materials, we have applied a combination of molecularly imprinted technology and amphiphilic block copolymers on MOFs for the first time. Amphiphilic PAVE copolymer is selected as the molecular imprinted functional monomer to improve the hydrophilicity of UiO-66-NH₂. The synthesized PAVE-MOF-MIP has adequate water dispersion ability and fluorescence activity. When encountering oxytetracycline, PAVE-MOF-MIP will produce fluorescence quenching, it is used to construct a fluorescence detection platform for oxytetracycline detection. Compared with traditional MIP@MOF, PAVE-MOF-MIP has better water dispersion ability and detection accuracy. Under optimal conditions, the linear range of oxytetracycline detection is 10–100 μmol L⁻¹, and the minimum limit of detection (LOD) is 86 nmol L⁻¹. This paper proposes a novel approach to use amphiphilic block copolymers as molecularly imprinted monomers on MOFs, providing an innovative idea that has not been previously explored.